DP Physics (first assessment 2025)

Question 19M.2.HL.TZ2.11cii

Date	May 2019	Marks available	[Maximum mark: 2]	Reference code	19M.2.HL.TZ2.11cii
Level	HL	Paper	2	Time zone	TZ2
Command term	Calculate	Question number	cii	Adapted from	N/A

cii.

[Maximum mark: 2]

19M.2.HL.TZ2.11cii

(cii)

Calculate, in hours, the time at which the activity of the sample has decreased to one-third of the initial activity.

[2]

Markscheme

$\frac{{\text{1}}}{{\text{3}}} = {e^{ - \lambda t}}$ ✔

t = 20«hr» ✔

Examiners report

This was very well answered with the majority of candidates scoring full marks. This is a good indication that candidates weren’t short of time in this paper.

Syllabus sections

E. Nuclear and quantum physics » E.3 Radioactive decay

Question 19M.2.HL.TZ2.11cii

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